Neural tumors such as glioblastoma (GBM) remain amongst tlie most difficult to treat. We have been interested in using oncolytic viruses, based on herpes simplex virus type 1 (HSV-1), as a selective nervous system tumor-killing virus. Considerable effort in the vector development resulted in the engineering of oncolytic HSV vectors (oHSV) such rQNestin34.5 that are non-toxic for normal cells, yet capable of selective replication in GBM tumor cells. In order to effectively use oHSV in animal tumor models it is necessary to propagate and purify oHSV to high titers. Efforts in process development have resulted in scalable systems capable of manufacturing rQNestin34.5 and other oHSVs. My laboratory has spent considerable time developing refined and novel methodologies to improve virus production, purification and quality assessment to provide high quality vector stocks with dramatically reduced levels of protein and DNA contaminants (>99% removal) that can contribute to toxicity, immunity and biodistribution as well as confound in vivo efficacy studies. Our efforts in process development have resulted in scalable systems capable of manufacturing these vectors for pre-clinical efficacy and safety testing resulting in a 10 to 30-fold increase in overall virus yield and a corresponding 60-fold increase in concentration of the virus. The Core is in the unique position of being one of a few sites for oHSV virus vector production, purification and quality assessment testing. This extensive expertise along with our prior collaborative interaction with the projects (33 oHSV vector stocks produced and distributed since October 2007) supports the overall success ofthe current proposal. The primary goal of the oHSV Production Core is to provide large quantities of GLP-grade concentrated and purified oHSV vectors: (i) rQNestin34.5 for Aims 1 & 3 of Project 2, Aim 1-3 of Project 3, and Aims 1-3 of Project 4; (ii) transductional retargeted/miR-regulated oHSV vectors engineered in Aims 1-3 of Project 1, or (iii) ChaseABC armed versions of rQNestin34.5 for Aims 1-3 of Project 3 or the ChaseABC-armed retargeted vector engineered in for Aim 2-3 of Project 3. The oHSV Production Core m\\ work with the projects to provide optimal vector quantity and purity while providing the support necessary to,successfully exploit the available technology. We will continue to refine our production, purification and assessment systems. Should any of the engineered oHSV vectors tested in the projects prove efficacious, the Core would provide support to cGMP facilities for transfer of the production/purification technology of large-scale oHSV manufacture for possible Phase-1 human clinical trials.